This invention relates generally to barriers or dividers suitable for blocking or dividing roadways and particularly to a barrier section having internal ducts and passageways for providing drainage and a conduit for cables, such as electrical or telephone cables, and method of construction of such a barrier.
It has become conventional practice to employ a barrier for separation oppositely directed traffic lanes. Such barriers may be either permanently emplaced in the center divider between lanes or temporarily emplaced to direct traffic away from particular locations, such as construction sites in or adjacent roadways. The barriers are formed to prevent automobiles from crossing into the path of oppositely directed traffic and therefore prevent "head-on" collisions. Typically such barriers comprise a plurality reinforced concrete sections placed end-to-end to extend a desired length, which may vary from several feet to many miles. Some barrier sections include coupling means for securing adjacent ends together to form a continuous rigid structure.
Such barriers typically include a base portion that has a generally rectangular or trapezoidal cross section, a tapered intermediate portion and an upstanding portion that may also be tapered. The base ordinarily rests upon or is embedded in the center divider between lanes. The lowermost edge of the base is generally the widest portion of the barrier. The intermediate portion tapers from the width of the uppermost edge of the base to the width of the lowermost edge of the upstanding portion.
Although these conventional barriers have been successful in preventing vehicle crossover from on lane to another, difficulties have been encountered which stem largely from the fact that low spots in the roadway collect water, debris and other foreign matter and such collection provides an undesired hazard to the driver of the vehicle. Conventional practice provides for external drainage systems such as open channels, grooved surfaces and the like for conducting water from the roadway surface. Such practices have not been particularly successful due to the fact that puddles and exposed water does still exist since drainage takes time. Also, conventional barriers are not equipped to carry electrical cabling, pipes or other ancillary equipment.
U.S. Pat. No. 4,105,353 issued Aug. 8, 1978, to Bork, et al. discloses a barrier having a longitudinal internal drainage duct extending the length thereof through the base and a smaller diameter passageway through to the intermediate portion. The duct is suitable for use in a drainage system for carrying water. Both the duct and the passageway are suitable for carrying telephone and electrical wires or the like. When used in a drainage system, the ducts have side openings extending therefrom to the outer surface of the barrier so that water may flow into the ducts. The barrier has a male end and a female end so that a line of interconnected barriers may be formed.
The barrier disclosed in U.S. Pat. No. 4,105,353 functions satisfactorily to prevent vehicle crossovers into oppositely directed lanes and to provide conduits for drainage or cables. However, there are significant difficulties encountered in the fabrication of such barrier sections. The ducts are cylindrical, which means that a cylindrical mold must be included in the forms used for molding and curing the concrete of which the barriers are formed. After the concrete has been poured and cured sufficiently to maintain its shape while unsupported, the cylindrical mold must be withdrawn from the concrete, leaving a cylindrical passage or duct therethrough. Even though oil or other suitable substances may be coated onto the outer surface of the cylindrical mold before pouring the concrete, friction between the mold and the surrounding concrete may cause great difficulty in removing the mold. Removing the mold from the concrete is therefore time consuming and expensive, leading to a loss of productivity of workers and equipment. An alternative to removing the mold is to include a pipe of the desired length and diameter in the barrier section. Since modern roadway construction requires a great number of barrier sections, which should be manufactured as economically as possible, including pipes in the barriers is not generally regarded as an economically viable alternative to removing the molds from the barriers.
It is known to manufacture concrete piles with tapered passages; U.S. Pat. No. 1,598,059, but horizontal flow is not there contemplated.
Therefore, there is a need in the art for an improved roadway barrier and method of construction to provide lengthwise ducts with molds that are conveniently and easily removed from the barrier after the concrete has cured sufficiently to permit removal of the molds and which permit horizontal flow.